As human life and culture become diverse and complicated with industrial development, various types of disposable tableware have been produced to save time, including spoons, cups, dishes, lunch baskets and other disposable living necessities.
Currently used disposable tableware is mostly made using synthetic resins (e.g., polystyrene), pulp, and the like.
However, disposable products manufactured using synthetic resins contain ingredients harmful to humans. Also, they are major causes of environmental contamination due to problems associated with waste disposal by their increased use, and thus have a limitation in use.
In addition, paper products manufactured using pulp have the following problems: they are not economical because most raw materials including pulp are imported; forests have been damaged in the production of the raw material, pulp, resulting in environmental disruption; and pulps are treated with synthetic additives during processing, thus causing environmental contamination. These problems may be partially solved by recycling used pulp. However, enormous energy is required for the recycling of pulp, and various additives are used in a recycling process, thereby bringing about secondary environmental contamination. Also, pulp is typically waterproof-coated with vinyl to solve its structural problems. However, these coated products have been also restricted in use by various environmental regulations because they cause environmental contamination.
Thus, in restaurants and other places, this disposable tableware is inconvenient to use because they should be recovered separately from other general wastes after being used.
This restriction in the use of disposable tableware is because most conventional disposable tableware is not environmentally degraded and thus cause contamination of the soil when buried under the ground or produce environmental contaminants such as dioxin when burned.
To solve these problems, efforts were made to develop environmentally degradable disposable tableware. However, the resulting tableware is problematic in terms of requiring high production cost and not being practical.
Environmentally degradable disposable tableware will be described in detail, as follows.
In recent studies, attempts were made to replace polystyrene with natural polymeric materials obtained from starch from grains or wheat flour, crop residues, and the like.
Grain flours may be used as described in Korean Pat. Publication No. 96-0006565 which discloses a method comprising mixing and kneading wheat flour, starch, baking powder and salts, molding the resulting dough, and freezing and coating the molded dough, or in Korean Pat. Laid-open Publication No. 99-0047173 which discloses a method comprising mixing and kneading main materials, starch of grains and wheat flour, with auxiliary materials including sugars, aromatics and yeasts in purified water at a proper temperature, maturating the resulting dough, extruding the maturated dough, and molding, freezing and drying the extruded dough. In addition, the grain crop residues may be used according to a method as described in Korean Pat. Application No. 99-0055567, which comprises mixing pulverized hulls from rice, barley, German millet, Indian millet, and the like, starch and water, and molding and coating the resulting dough, or another method as described in Korean Pat. Application No. 99-0037967, which comprises mixing vegetable particles used as a major material, prepared by pulverizing corn stalks or various seed coats, with an edible glue, and compressing the mixture with a molding agent.
However, the resulting products have limited applications because they are heavy, easily destroyed, and contracted by outdoor temperature.
To solve these problems, natural polymers have been used as main materials inevitably in combination with non-degradable additives. Thus, the resulting products are also problematic with regard to degradation and production cost, thus making their practical use difficult.